Determining line of sight (LOS) and range to a target are frequent problems in security and military applications. Determining the LOS available to a user based on a top-down, topographical map may be a time-consuming and error-prone task. Subtle or drastic changes in elevation can create areas to which a user does not have an LOS. Such areas, or blind spots, may provide locations where intruders can hide or crawl to go un-noticed. Such areas may also provide routes from which an intruder can approach or even penetrate a perimeter. For example, a region mapped on a topographic map with five meter contour lines may appear, on the map, to be flat and exposed, and thus not a likely route for intruders. However, a three meter deep gully may meander through the region, providing an approach route that is invisible on the map because the three meter depth of the gully is smaller than the map's five meter “resolution” can resolve. Similarly, a panoramic image provided from a panoramic imaging device may also not display the gully, especially if the terrain is covered in a relatively uniform material (e.g., grassy plains, desert scrub, snow), or if the image is a relatively low resolution thermal image. Thus, conventional approaches to deploying limited resources (e.g., guards, soldiers, sentries, imaging devices) in a security or military situation based upon determining LOS from a topographical map may leave the gully unobserved, and may create a false sense of security.
Many cameras take panoramic images that are adequate for remembering a scene from vacation. While the panoramic image may be suitable for recalling a vacation moment, the panoramic image is unsuitable for security or military related applications where potentially life and death decisions concerning the delivery of ordinance or other active measures or countermeasures may need to be made in real-time. Conventional panoramic images tend to be acquired along a single axis and contain just the color or intensity information needed to display a digital version of the panoramic image. Conventional panoramic images do not contain accurate range information associated with objects in the image. Determining a range from a security or surveillance system to an object represented in an image acquired by the system is a difficult, if even possible, problem to solve, particularly in a tactically useful timeframe. While a human may be able to estimate a range to a target imaged in a panoramic visual or thermal image, the estimate is unlikely to be accurate enough to effectively or usefully guide ordinance or other resources to the target.
A panoramic imaging system may acquire multiple images (e.g., digital photographs) that when processed into a single image provide a larger field of view than is available in a single image. Conventionally there have been different approaches for acquiring the multiple images that are processed together into a single image that has a larger field of view. Regardless of how the multiple images are processed into the single image, the single image still tends to include just the color or intensity information needed to display a digital version of the panoramic image. These panoramic views have typically been unsuitable for certain military applications where real-time decisions need to be made based on surveillance imagery. In particular, these panoramic views typically lack reliable range information, if they contain any range information at all.
Conventional “staring” type cameras may operate in conjunction with a laser range finder co-aligned with the image data capture apparatus of the staring camera. However, conventional approaches that align a laser range finder with a static, staring camera are not practical if the camera needs to rotate, which panoramic imaging systems typically need to do. While rotation can be stopped to take a reading, a conventional system is not detecting targets in other directions when it is stopped. Thus, conventional systems that stop scanning to take range readings leave the remaining area of interest unwatched and open to exploitation.